LP_token拿不到approve状态数据

By zx on 2020-09-23

justswap LP token有很多问题，erc20的实现并不完整，

我调用approve方法，通过allowance方法并不能拿到approve的状态

// 构造合约实例
let address = window.tronWeb.address.fromHex(LPContractAddress)
let pool = window.tronWeb.contract(LPTokenABI, address)
// 获取用户address
const coinbase = window.tronWeb.defaultAddress.base58
// 调用合约方法
const res = await pool.methods.allowance(coinbase, poolContract).call()

上面调用会报错❌Failed to execute

经过一系列调查的研究，发现了两种方法解决问题

1. 部署合约代理

通过研究sun.io也做了LP的pool，他们部署了一个合约来代理这部分，https://tronscan.io/#/contract/TDQ6peySpWnmArP4Je8XXBp54j4h4vtzym/code

const address = window.tronWeb.address.fromHex(ValuesAggregatorAddress)
const pool = window.tronWeb.contract(ValuesAggregatorABI, address)
const coinbase = window.tronWeb.defaultAddress.base58
// 获取balance
const balance = await pool.methods.getBalance(coinbase, [LPTokenAddress]).call()
// 获取余额和approve状态
const balanceAndApprove = await pool.methods.getBalanceAndApprove2(coinbase, [LPTokenAddress], [PoolAddress]).call()

2. 通过triggerconstantcontract方法调用

tronweb链接：https://developers.tron.network/reference#triggerconstantcontract-1

const contractAddress = window.tronWeb.address.fromHex(LPTokenAddress)
const coinbase = window.tronWeb.defaultAddress.base58
const issuerAddress = window.tronWeb.address.fromHex(coinbase)
const func = 'allowance(address,address)'
const parameter = [
    { type: 'address', value: coinbase },
    { type: 'address', value: PoolAddress }
]
const res = await window.tronWeb.transactionBuilder.triggerConstantContract(
    contractAddress,
    func,
    {},
    parameter,
    issuerAddress
)